http://cms.cern.ch/cds/TOP-12-040
Ernesto
Type B
How the 6.1 sigma excess mentioned in the abstract is compatible with the ratio of the measured cross section to its error 23.4/5.5=4.3?
It is not clear how the choice of the “Diagram Removal” scheme concretely translates in the extraction of the cross-section. Are you applying a weight to the events of the powheg single-top sample (based on the matrix-element) reflecting the different likelihoods of being “s-channel”, “t-channel” and “tW” respectively and, within the “tW”, for being “DR” or “not-DR”? You should expand a bit this discussion.
About the “labels” of the three categories of events: why don't you name them “1b” “2b” and “1b1l” so that there is only one cardinal number representing the topology of the category (also in the current labels “t” is misleading as it suggests “top” - at least to me)
What is done exactly in the cross-check analysis? Is the BTD retrained after the two cuts (veto on the loose b-taggd jets and HT>160 GeV) or you just compute the significance?
Type A
L47 “performed” and “performing” appearing twice in the same line.
L54 “A more detailed description” → “A detailed description”.
L56-57 You are investigating three possible final states: ee, mumu, and emu but only DoubleMu and DoubleEle triggers are used in the analysis. How do you control the trigger efficiencies for the emu channel?
L58-59 as it is currently written, it seems that the selection is limited only to events with just one reconstructed PV. It should be emphasized that CMS is able to reconstruct many PV's and among them you choose as origin of the tW system the one with the highest sum_pT^2.
L68 just a curiosity: which is the composition of the sample in terms of ee, mumu, emu before and after the cut on m(ll)? Is the ETmiss>50 GeV cut applied only to the ee and mumu final states?
L81 “one jet passing the selection requirement which is b-tagged” → “one b-tagged jet with pT>30 GeV and |eta|<2.4”
L84-88 are the samples normalized to the cross-sections measured at LHC or those from the best theory predictions?
L85 “next-to-leading” → “NLO” (already defined earlier)
L95 “For all simulated samples…” this sentence about the choice of the PDF should be closer to the sentence describing the MC codes used (e.g. L90)
L108 expand a bit on which kind of background events is flagged by the presence of loose jets
L111 is there any better label than “sys” to indicate the leptons+jet+ETmiss?
L118 it should be mentioned that the results for ee, mumu and emu final states are consistent (if they are)
L124 why m_t is so relevant for the systematics? Which of the kinematic variables entering in the BDT is so sensitive to m_t?
L130 “u” at the end of the sentence looks ugly.
L132 “\delta” → “\der” ?
L142 “simulation”: do you mean pseudo-experiments using simulated data? (“pseudo-experiments” is probably jargon)
Figures: remove the text “emu/mumu/ee channels”
Nicolo`
Doubts:
L110: if in the sum you include the Et miss, don't it sum up to zero?
L114: These lines need to be rewritten a bit. The sentence: “with higher values indicating a more signal-like event” is not always true in the 3 regions.
The BDT analyzer is higher for the signal only in the signal region. In the other two regions, the signal is clustered around 0.
Abstract:
The observation…… with =⇒ The observation…… by
L11: The t-channel production channel has been observed at D0 ==⇒ The t-channel production channel has been observed at the Tevatron by D0… (to be symmetric with the following sentence)
L15: , but evidence =⇒ , while evidence
L20: of interest because of the =⇒ of interest due to the
L23: for the cross section for =⇒ for the cross section of
L24: at approximate next-to… =⇒ “approximate” is this a correct expression?
L29: that the issue is resolved =⇒ that the separation is obtained
L35: The analysis presented in this Letter is performed using the dilepton decay channel =⇒ The analysis is performed using dilepton decay channels
L37: a neutrino, with =⇒ a neutrino, a process with
L41-42: defined as the magnitude of the negative =⇒ defined as the negative magnitude
L43: production in this final state =⇒ production decaying in these final states
L58: define “primary” vertex?
L76: but passing a less .. requirement =⇒ but passing the less…. requirements
L80: are defined =⇒ are identified
L81: a signal region is not defined as having a given class of events, but by a requirement. based on events with exactly =⇒ based on the requirement of having exactly one jet… which is b-tagged =⇒ together with the b-tagging request
L81-83: as they are defined as “b jets”, maybe the name should have the “b” and not the “t”: 1j1t =⇒ 1j1b…
L91: after the lepton selection =⇒ after the leptons selection
L93: , and the =⇒ , with the
L94: simulation has been reweighed to match =⇒ simulation matching
L105: , chosen based on =⇒ , chosen for
L121: threshold =⇒ thresholds (in the table is plural)
L127: distribution in =⇒ distributions of
L128: and three control regions =⇒ in the three regions
Table 2: “fixing each source one at a time” Not sure: Is this what you do? fix one or let one free? =⇒ “varying a single source at a time”
section uncertainty =⇒ section value I guess you evaluate the change in the value of the cross section, not the change in its uncertainty
L148: cross section assuming =⇒ cross section setting